For anyone who hoped that the tragedy in Tucson might jolt the political class into some new period of civility and reflection, suddenly subduing all the radio ranters and acid bloggers, the days that followed brought a cold reality.
Within hours of the shooting rampage that killed six and critically wounded Representative Gabrielle Giffords, liberals were accusing conservatives of inciting the violence, and conservatives were accusing liberals of exploiting the actions of a madman.
So far, so fair, though the column is built on the faulty premise that the heated political atmosphere played a part in Loughner's rampage. But then Bai goes awry, overstating Oklahoma City bomber Tim McVeigh's ties to the right and falsely claiming Sen. Max Cleland's patriotism was attacked in a 2002 campaign ad.
Of course, this kind of shift is probably never so apparent in real time. It may be that in 50 years, historians will look back at the last week and say that a long period of shrill, fear-inducing politics and escalating vituperation, which seemed to paralyze our politics at a time when we could little afford the inaction, began to fade at last as a horrified nation buried a 9-year-old girl and prayed for a congresswoman to wiggle her toes.
There are good reasons to think, though, that such defining moments are simply relics of our past, like air raid drills and loyalty oaths. There was a brief time, after 168 people were killed in the 1995 bombing of the Murrah federal building in Oklahoma City, when it seemed that all the extremism on the right had been deflated. But the impact of the blast receded so quickly from memory that Michael Kazin, a Georgetown historian, says a lot of his students today had never heard of it.
Not even the terrorist attacks of 2001, which surely rank high among the most jarring events in American history, did much to unify the society in any lasting way. The collapse of the World Trade Center towers had immediate and significant consequences for the nation's foreign policy, but any sense of common purpose had more or less vanished by the next year's elections, when Republicans slammed their Democratic opponents - including Max Cleland, a man who lost three of his limbs fighting in Vietnam - as insufficiently patriotic.
Sigh. The Times has been fostering for years the myth  that an ad by Republican opponent Saxby Chambliss cost Cleland his 2002 election by unfairly maligning his patriotism (Chambliss won). If you're more curious about the actual ad than is the average Times reporter, you can watch it on You Tube 
Over a montage of four photographs, one each of bin Laden and Saddam Hussein, two others of the U.S. military, a narrator reads: "As America faces terrorists and extremist dictators, Max Cleland runs television ads claiming he has the courage to lead." The ad then points out Cleland voted against Bush's Homeland Security efforts 11 times.